Talking doll and action driven circuit therefor



June 24, 1941. G. DElTZ 2,247,329

TALKING DOLL AND ACTION DRIVEN CIRCUIT THEREFOR Filed 00%. 5, 1939 2 Sheets-Sheet l INVENTOR 650365 05/ T Z June 24, 1941. G. DEITZ 2,247,329

TALKING DOLL AND ACTION DRIVEN CIRCUIT THEREFOR Filed Oct. 5, 1939 Z SheetS-Sheet 2 AVEQAG'F PLATE Cl/REENT M14.

0 I Z 3 4 5 6 SIGNAL 2M5 701.75

0 Z 4 6 8 IO l2 l4- l6 I8 20 SIGNAL "RMJ' VOLTS INVENTOR GEORGE 05/7:

I Patented June 24, 1941 TALKING DOLL AND ACTION DRIVEN CIRCUIT THEREFOR George Deitl, Brooklyn, N. Y., assignor, by mesne assignments, to Richard E. Beck, Chicago, Ill.

' Application October 5,1939, Serial No. 298,008

8 Claims.

The present invention relates to so-called living figures having a human, animal or grotesque shape, such as dolls, robots, etc.

The present invention contemplates the provision of such a figure (which for the sake of convenience will hereafter be called merely doll") which is selectively capable of projecting audio waves transmitted to the doll from a remote point and of picking up audio waves in the vicinity of the doll and transmittingthem to the aforementioned remote point. It is to be understood that by audio waves picked up at the remote point or in the vicinity of the doll it is intended to also include sounds ori inating from recordings, and electrical impulses corresponding to sounds such as are derived from photographic sound tracks and other types of recordings.

The present invention further contemplates the provision of means whereby some member of the doll, such as for instance the doll's jaw, may move in relation to the audio waves picked up at-a remote point and subsequently projected by the doll, and the present invention contemplates the simulation of a living creature, by

' causing the doll to project sounds while simultaneously moving its jaw in definite relation to the sound projected.

The present invention further contemplates the provision oi such a device which is comparatively simple to construct and operate, comparatively inexpensive in operation and construction, easy to repair, and not likely to get out of order'easily.

Further objects and purposes of the present invention will become apparent from the following description and the drawings in connection therewith in which Fig. l is a sketch of a doll showing the arrangement of a loud speaker and a jaw moving solenoid therein and the circuit for operating the above mentioned speakerand solenoid from a remote point.

Fig. 2 is a graph showing the normal operation of a power-amplifier tube in a standard circuit. I

Fig. 3 is a graph showing the operation of the power-amplifier tube in the circuit used in the present invention to furnish the power for moving the doll's jaw. 1

As stated heretofore, the present invention contemplates the provision within a doll oi means for projecting audio waves therefrom and means for picking up sounds within the vicinity oi the doll by means located within the doll and transmitting said sounds to a remote point. It is, of course, to be understood that these means may also be located outside the doll in proximity thereto.

While there are many diiierent types of means for projecting sound which may be located within the doll, it is preferred that a dynamic speaker iii having a permanent magnetic field maintained by a permanent magnet H be utilized. A movable coil l6 designed to oscillate in accordance with sound waves impinging thereon is inserted into the magnetic field. This construction is not new and is well known so that the exact functioning of this type of speaker will not be explained.

While it is possible to use a separate microphone and a separate speaker, it is preferred that the speaker iii serve both functions since this simplifies the circuit and is more economical. When speaker I0 is used as a microphone, it will be readily apparent to anyone versed in this art that as the coil i6 oscillates because of sound waves impinging on the speaker iii, the.

coil cuts the lines of the permanent magnetic field set up by the permanent magnet i2 and an alternating current is induced in the cofl i! having a sinusoidal wave form. A similar type of speaker I8 may be located at a remote point, that is at any point outside of the doll, and may be connected through an amplifying circuit to the speaker i0.

While there are various methods of connecting the two speakers together and while there are very many difl'eren-t types of amplifying circuits that can be applied therebetween to amplify the signal, I prefer to utilize the method 01' connection and the type of amplifying circuit hereafter described.

When the speaker iii is used as a microphone, that is for the purposes of picking up audible sounds within the vicinity of the doll, the sound picked up causes the coil it to vibrate setting up alternating currents therein. These currents are next transmitted to an audio amplifier for the purpose of building up said currents.

The coil i6 is connected to the primary 2| of an input step-up transformer 22 by grounding one side 24 of the coil i6 and by connecting the other side 26 to one pole of a switch 30, which switch 30 may be a rotary switch having three separate segments 32, 34 and 36 designed to move together, each of said segments connecting at one time two poles of the three poles with which said segment is designed to make contact.

It will be seen that when the rotary switch is in the position illustrated, segment 32 will connect conductor 2| leading from the coil II to one end of the primary 2| the step-up transformer22. Theotherendoftheprimaryis grounded as is the other end of the coil N, thereby completing the circuit through the ground. With the switch in the position illustrated, which will be called position "A" hereafter, it will be seen that the current from coil M is impressed upon the primary 2| of the step-up transformer. The alternating current in the secondary of the input transformer 22 is impressed upon the grid of an amplifying tube 4| through a grid condenser of the proper capacity to correspond to that of the tube utilized. As two stages of am plification are used here, the first tube selected is preferably a "C" type amplifier (voltage amplifier) so that an amplified variation of the voltage will be impressed on the second tube. The voltage amplifier selected may be a pentode of the 606 type having an indirectly heated cathode and a controlled grid, a screen grid, a suppressor connected with the cathode, and a plate or anode. With this tube, it has been found that a grid condenser 42 having a capacity of .002 to .005 mfd. is preferable. A grid leak of fifteen megohms resistance is connected between the grid and the cathode circuit. The grid is negatively biased because of the high contact potential existing in high Mu tubes (tube 40 is a high Mu tube). The grid, being in the path of the electron stream, picks up a negative charge and is maintained at a constant negative potential. To prevent the tube from becoming blocked as a result of a powerful incoming voltage, the high resistance 44 of 15 megohms is provided to allow excessive charges to leak oil.

The connections for the filament and cathode are not shown as they are standard and well known to those versed in the art. The plate of the tube II is connected to a source of positive potential (B+) through a resistance of .5 megohm. This may vary according to the tube and preferably should be 100 volts or more. The source of the supply is not shown as this too is well known in the art and may consist of either a battery or a rectifier operating on alternating current. The screen grid may be connected to the same source of supply through a .2 megohm resistance so as to have a relatively lower potential than the plate. A condenser 43 of .01 mfd. capacity or more may be connected between the cathode and the screen grid, this condenser serving to aid the passage of lower audio frequencies through the circuit. The plate of the tube 4| is connected through a .01 mfd. condenser to one end of a potentiometer 4|, the opposite end of which is connected to the cathode circuit, the variable arm 5| of the potentiometer being connected to the grid'of the tube 54. By moving arm 5|, the amount of amplification may be controlled.

The tube 5| is preferably an A-type tube (power amplifier) and delivers a heavy current output. For this purpose, I prefer to provide a pentode of the 25A7G variety. As stated before, the grid is connected through the potentiometer 4| and the cathode is connected to the cathode of the preceding tube through a 600 ohm resistance 5|. The 5 mfd. condenser 51 is placed across this resistance to prevent feed back of the current into the first tube which would cause e eneration.

The grid of tube 5| is kept at a negative potential. By means of the inter-electrode capacity (condenser-elect) between the Bid and the cathodathecathodewhichirpmitivedue totheplatecurrentinducesanegativednrgeon,

thegridwhichchargeismaintainedaclmthe resistor. Thescreengridofthetubellis connected to a suitable positive potential source.

Theplate'ofthetubeilisconnectedwiththe.

primary ll of a step-down output transformer 6|, the other end of the primary being cmnectedtothesourceofBsupply. Asmallcondenser is connected between the plate andthe ground to by-Pfls any parasitic high mm oscillations thatmayoccurintheplatecircuit.

One end of the secondary 1| of the output transformer is grounded. The other end is connected to the coil I2 of the speaker l| through the switch 2|. It will be seen that when the switch 3| is in position A that the segment 3| will connect the central pole thereof with the outer pole which is connected to one end of the coil I2. The other end of the coil 12 is thus making a complete circuit between coil 12 and the secondary ll of the output transformer 6|.

From the foregoing, it will be seen that when a signalisreceived bythespeaker i|,itistransmittedto the switch 2| through the amplifier and the tubes 4| and SI thereof to the speaker l8, thereby delivering an amplified sound at speaker II.

The type of amplifier selected here is what may be generally described as a resistance canpled amplifier and such type of amplifiers are being used more frequently than heretofore because of the fact that it does not distort the signal and that it is relatively inexpensive to construct. I

If it is desired that instead of the sound being picked up at I0 and projected through speaker ll that instead the sound be picked up it 8Dfiler II and projected through speaker II, the switch 3| is moved co1mterclockwise so that the segments thereof only connect the central pole at eachsegment with the pole immediately counter-clockwise thereof, and not with the pole clockwise thereof. It will be seen that in this pomtion, called position B, of the switch that if any sound impinges on the speaker II and moves coil N, the current in coil I| will not be transmitted to the primary 2| of the input transformer 22 because the se ment of the switch 8| will not complete the connection therebetween. lnsteadifasoundimp s sonthespeakerll moving its coil 12, an alternating current will be setupinccili2.oneendofwhichisgrounded and the other end of which passes through the switch to one end of the primary 2|. As stated heretofore, the other end of the primary 2| of the input transformer 22 is Therefore, there will be a complete circuit formed betweenthecoilflofspeakernandtheprimary of the input transformer 2|. It will be seenthatthiscurrentwillpasthrmightheampliiier as hereinbefore described and will be impremed on the output transformer It will be seen that as before one end of the output tram former is grounded. The other end passes through the switch 3| through the t 8| and thentothe coil N of thespeaker II.

It will be seen, therefore, that by turning the switch sound can be transmitted from speaker II to speaker l| or vice versa, whichever position of the switch is selected.

when sound is transmitted from speaker II to speaker llandtherotaryswitchisinpodtion B hereinbefore described, another result follows.

It will be seen that there is a direct connection through a .002 mfd. condenser 18 to the center pole of the portion of the switch on which the segment 36 operates. In position A, no connection is formed therethrough, but in the position B of the switch 30 the center pole is connected with the grid of a tube in another circuit.

This circuit, which will be called the action driver circuit, is shown in Figure 1 within the area formed by the broken line. This action driver circuit is not conventional and, therefore, will be described in detail.

When the switch 30 is in position B, a portion of the plate current of tube 54 is impressed through condenser 18 on the grid of tube 90. As this action driver circuit is intended to move the jaw of the doll, it is desirable that it have a very heavy current output. Therefore, it is preferable that an A-type tube be used (power tube). For this purpose, I prefer to utilize a pentode of v the solenoid 94 will be at a maximum and will,

therefore, pull the plunger 96 to its lowermost position, keeping the mouth of the doll closed.

When, however, a signal is impressed through the amplifying system onto the grid 90 of the tube, a different result occurs.

Any further positive impulses impressed on the I grid of the tube would have little or no effect as the typeknown as the L6 (Beam type tube).

The cathode of the tube 90 is grounded. The grid and cathode of the tube 90 are connected through a one megohm resistance 92. It is important to note that there is no negative bias on the grid but that the cathode and grid are substantially at the same potential since they are connected together through a relatively low resistance. The screen grid of the tube 90 is connected through a three thousand ohm resistance to a positive potential source (B+).

The plate of the tube 90 is connected through a solenoid 94 to the B+ supply. Inside the solenoid, a plunger 96 is positioned which responds to the current in the solenoid as will be hereinafter described. The plunger 96 has its innermost end 98 formed into a point to conform in shape to the plug I00 of the core I02 of the solenoid 94, the purpose of having the point 98 being to provide a relatively shorter gap between the plunger at its farthermost position and the plug I00 of the core I02 thereadjacent so that less force will be necessary to move the plunger inward toward the solenoid.

The plunger 96 may be connected with the jaw I04 of the doll through a link I06 pivotally connected with an arm I08 which forms a lever with the jaw I04, said lever pivoted on the pivot IIO. It will be seen that when the plungeris released by the/ solenoid, it will be moved upward by the action of compression spring II! which forces the jaw downward around pivot IIO raising arm I08 and then the arm I06 and plunger 96. When sufficient current, however,

the tube ,is' already operating at its maximum plate current andmaking the grid positive would not materially change the plate current. On the other hand, making the grid negative would have a material effect on the plate current because it would retard the flow of electrons-from the cathode tothe plate and would, therefore, lower the current in the plate circuit of the tube 90. The current in the coil of the solenoid 94 would then be lessened and the pull on the plunger would also be lessened so that the spring H2 would open the jaws of the doll as it pulls the plunger upward.

It is important at this point to note to what current variations the plunger 96 will respond.

Because of its inertia, it will not move in synchronism with the audio frequency vibrations of passes through the solenoid 94, it will pull the plunger down against the resistance of the compression spring I I2 and close the jaw of the doll. In short, when there is a suflicient amount of current in the solenoid to pull the plunger 96 down, the jaw of the doll will be closed and will only open when that current lessens sufllciently to allow the spring I I 2 to open the jaw.

The spring is so adjusted that when the current in the plate circuit of tube 90 is at its maximum the dolls jaws are closed,

.A more detailed description of the operation of the action driver circuit" will now be given. It is of the utmost importance to note that the tube 90 operates with no grid bias on the grid of that tube. This has an effect on the tubes operation which will now be explained. With no the electric current. Therefore, if the current in the solenoid consisted of audio frequency vibrations about a fixed average current ,,the jaw of the doll would not respond-at all, as the jaw would move too slowly to respond to the audio frequency vibrations and, if the average current was fixed and stationary, the jaw of the doll would be stationary, too.

Even if it were feasible to make the jaw vibrate at audio frequency, it would not be desirable as the eye could not follow the movement. A much slower movement of the jaw is sought.

The present invention takes advantage of the fact that the amplitude changes of speech vary much more slowly than do the crests and troughs of sound vibration. The jaw of the doll is made to vary with the variation of the amplitude of sound, that is with the sound envelope, not with the variation of each individual vibration of sound. This is accomplished by causing the plate current of the tube to vary with the effective voltage impressed on its grid.

The foregoing will be more readily understood from an examination of Figs, 2 and 3.

Fig. 2 shows the relation of the average current in the plate circuit to the effective voltage of the impressed signal'on the grid of the tube.

Fig. 2 shows the relation between the RMS signal volts impressed on the grid and the average plate current output when the grid of the tube is biased (in this particular type of tube to eight volts negative), the almost horizontal line on Fig. 2 across the grapherepresenting the average current inthe plate. While with an incoming signal varying at audio frequency the plate current rises and falls above and below the level of the line shown in Fig. 2, the average of the peaks and troughs is that indicated. by the substantially horizontal line as stated hereinbefore, noid could not rise and fall with the crestsand troughs of the audio frequency cycle, it would follow the average plate current and would, therefore, remain absolutely stationary. When the tube is used along the line shown in Fig. 2,

of Fig, 2. Since, the plunger of the sole-' it operates as an ordinary audio amplifier because the audio frequency crests and troughs of the input signal are reproduced in amplified form in the plate circuit along the line of Fig. 2 and the crests and troughs are equally ampli- 5 iied so that there is no distortion of the impressed signal. As explained, however, such nondistortional amplification would have no effect upon the jaw moving mechanism described herein which responds only to changes in the average plate current. It, therefore, becomes necessary that the tube be operated along the characteristics which would cause distortion of the signal so that-there would not be a uniform average current in the plate circuit but that the aver-age plate current in the circuit would vary. and it is preferred to make the plate current vary in the plate circuit inversely as the signal RMS volts increase.

It is found that the tube 90 when operated without any grid bias produces a plate current of sixty milliamperes when no signal is incoming, When a signal fluctuating at audio frequencies is impressed on the grid of this tube, it is found that the plate current falls on in exact proportion as the signal RMS voltage increases. That characteristic of the present circuit has been shown in Fig. 3 and it will be noted that, when the signal RMS voltage is 20, there is an almost complete stoppage of plate current. The explanation of the falling line illustrated in Fig. 3 is that the positive portion of the incoming signal sinusoidal wave has little effect upon the plate current as the plate current is already at a maximum and the tube will not, because of its characteristics, give a greater plate current even if the grid is made more positive. On the other hand, the negative portion of the sinusoidal wave of the incoming signal causes a proportionately amplified drop of the current in the plate circuit. It will be seen, therefore, that only the negative portion of the sinusoidal wave is amplified, therefore, as the signal RMS voltage increases the plate current will decrease proportionately.

As explained in connection with Fig, 3, the action driver circuit herein described which has no negative bias on the grid will respond to an incoming audio frequency signal in two distinct ways. One aspect of the current in the plate circuit will be an 'audio frequency fluctuation therein corresponding in distorted fashion to the audio frequency vibrations of the signal. The other phase of the current in the plate circuit will be the fluctuation of the average plate current in accordance with the fluctuation of the signal RMS voltage impressed on the grid of tube 90.

It is to be noted that when an audible sound operates the coils of either of the speakers that a sinusoidal current wave is set up in said coil. This sinusoidal wave has two components, one consisting of current changes from a positive peak to a negative peak at audio frequency and conforming to the pitch of. the voice, and another component which might be called the amplitude envelope and corresponding with the changes in amplitude of the sound impressed which changes are below audio in the frequency of their occurrence. It is to this latter ampli- 7 tude envelope that the jaw of the doll will respond and it is to this phase of plate current variation expressed in the variation of the average plate current to which the plunger 98 will respond synchronously. It will thus be seen that changes in the amplitude of the voice speaking into speaker II will cause corresponding changes in the position of the law I of the doll. This change will be in proportion to the amplitude of the impressed sound reaching speaker I8.

If greater power is desired than that given by the tube I, a saturable reactor may be connected in the plate circuit of the tube 90.

By the use of a saturable reactor, a large amplification in the current output is produced several times as large as that passing through the plate current circuit of the tube. As such saturable reactors are well known, they will not be described here.

From the foregoing description, it will be seen that a device of the general character described has been provided by which the illusion of a doll speaking may be created and by which a doll can be made to appear both to speak and to listen. This device might be used for advertising purposes and might be controlled by a person concealed at some remote position from the doll so that when anyone speaks to the doll the listener at a remote point might reply and the reply seem to emanate from the doll itself.

It will further be seen that the doll's jaw only operates when the doll appears to be speaking, not when the doll appears to belistening.

While I have described an embodiment of the present invention in specific detail, I do not intend to be limited to the specific details herein set forth, but intend that the scope of the present invention be determined by the claims for it is to be understood that the various values of potential, capacity and resistances used herein and the specific circuits used may be varied in accordance with the specific characteristics of the tubes, solenoids, etc., used without departing from the principle of the present invention. These values may also be varied to determine the tonal qualities of the reproduced sound.

I claim:

1. A doll having a movable part, selective means for transmitting electrical impulses corresponding .to audio waves from a distant point to said doll or for transmitting electrical impulses corresponding to audio waves, originating near the doll, to said distant point and means for moving said movable part in synchronism with the amplitudes of said impulses transmitted from the distant point to said doll, said means including a thermionic relay circuit, the current impressed on the plate circuit of which is normally maintained substantially at a maximum.

2. A doll having a movable part, selective means for transmitting electrical impulses corresponding to audio waves from a distant point to said doll, and means for moving said movable part in synchronism with the amplitudes of the impulses, said means including a thermionic relay circuit, the current impressed on the plate circuit of which is normally maintained substantially at a maximum.

3. A doll having a movable part, selective means for transmitting electrical impulses corresponding to audio waves from a distant point to said doll, and means for moving said movable part in synchronism with the amplitudes of the impulses including a thermionic relay having a grid electrode normally at ground potential.

4. A doll having a movable part/means for transmitting electrical impulses corresponding to audio waves from a distant point to said doll and means for moving said movable part in synchronism with the amplitudes of the impulses, in-

eluding a thermionic relay having a grid electrode which is grounded' 5. A doll having a movable part, means for transmitting electrical impulses corresponding to audio Waves from a distant point to said doll, and means for moving said movable part in synchronism with the amplitude of the impulses, in-

7. A doll having a movable par-t, means for transmitting electrical impulses corresponding to audio waves from a distant point to said doll, and means for moving said movable part in synchronism with the amplitudes of the impulses, including a thermionic relay circuit having an unbiased grid, whose average plate current is inverse to the effective voltage on the grid electrode within the operating range of the thermionic relay.

8. A doll having a movable part, selective means for transmitting electrical impulses corresponding to audio waves from a distant point to said doll and means for moving said movable part in synchronism with the amplitudes of the said impulses including a grid electrode and a cathode normally maintained at the same potential.

GEORGE DEITZ. 

